Fuse construction



March 22, 1938. R. A. HAMMACK FUSE CONSTRUCTION Filed NOV. 8, 1935Patented Mar. 22, 1938 UNITED STATES PATENT OFFICE FUSE CONSTRUCTIONApplication November 8, 1935, Serial No. 48,837

3 Claims.

This invention relates to a fuse construction. Objects of this inventionare to provide a very simple type of fuse construction which may be usedin any capacity but is eminently suitable for use as a secondary fuse.

It is well known that where very small amperage primary link fuses areused when fusing a transformer for instance, that it is usually thepractice to use nothing smaller than a 3-ampere 1O fuse for example,with the result that there is often over fusing of the smallertransformers, particularly of the 13,000 volt class, and secondary fusesare therefore necessary for overload protection. Additionally, it isadvisable to use secondary fuses where there are grouped secondaries ofthe transformers to prevent outage of the entire group in case offailure of a single transformer.

This invention is designed to provide a simple type of fuse which may beused as a suspension fuse and therefore does not require any additionalroom on the cross arm of a pole, for example, but which may be employedas a suspension fuse directly in the secondary line so that the minimumspace is required.

Further objects are to provide a novel form of suspension fuseconstruction in which a porcelain body portion is employed and is sojoined to the line wires that the porcelain is placed under compression,and in which no strains are imposed on the fuse link or fuse member,such fuse member being held in spaced relation to the line wires andbeing so held that it may be very readily refused.

In some of the previous constructions of suspension fuses it has beenthe practice to provide a separate insulating block which acts as amounting member for the fuse link. This invention, however, has for itsfurther object the 4.0 provision of a suspension fuse in which thestrain member also serves as a spacing member for the fuse link.

Further objects are to provide a construction which is easy to install,which is reliable in operation, and which may be placed in any positiondesired, either horizontally, vertically, or in an angular position.

An embodiment of the invention is shown in the accompanying drawing, inwhich:

Figure 1 is a side elevation with parts broken away showing the fuseconstruction.

Figure 2 is a plan view of the structure shown in Figure l.

55 Figure 3 is a sectional view through the porcelain insulator, suchview corresponding to a section on the line 3-3 of Figure 1.

Referring to the drawing, it will be seen that the porcelain bodyportion has been indicated by the reference character I. This porcelainbody portion is provided with a plurality of pairs of channels 2 -2, and3-3 located in diametric relation to each other. The channels 3-3communicate with an opening 4 extending transversely through theporcelain insulator and the 10 channels 22 communicate with an opening 5extending transversely through the porcelain insulator and arranged atright angles to the opening. 4.

The line wire 6 is passed through the opening 15 5 and lies within thechannels 2. It is looped back upon itself and twisted or otherwiselocked in place, as indicated at l in Figures 1 and 2. The line wire 8is passed through the opening 4 and lies within the channels 3. It islooped back upon itself similarly to the line wire 6 and is twisted orotherwise looked, as indicated at 9.

Bracket members 10 and II are bolted toopposite ends of the porcelainbody portion l in any suitable way, as by means of bolts or screwscemented into the porcelain body portion as indicated in Figure l, andhave outwardly turned terminal portions.

Any convenient means may be provided for bolting the bared ends of theline wires 6 and 8 to these terminal members and for clamping the fuselink hereinafter described in place. For example, screws I2 may passthrough the members l0 and H and may be provided with nuts I3 and thumbnuts M.

The bared end of the line wire 6 is secured to the terminal member i0,suitable washers being positioned on opposite sides of the bared end ofthe line wire 6 and such end being clamped in place by the nut l3. Thebared end of the line 40 wire 8 is similarly locked to the terminalmember H.

A fuse link 15 is supported from the terminal members, preferably beingheld between washers and locked by the thumb nuts 14, as. indicated 4:"most clearly in Figure 1.

The fuse link 15 is thus spaced a considerable distance from the linewires and also is spaced from the porcelain member. It is not subjectedto any mechanical strain whatsoever.

The member 2 is preferably of porcelain. or glass to prevent seriousburning and carbonizing from the are when the fuse blows under heavycurrent. Also it is to be understood that if it is desired, the fuselink may be enclosed in a fiber or protective tube to prevent metallicdeposit from the fuse link or any damage to the insulator when the fuseblows, though generally this is not found necessary.

It is obvious that these fuses may be placed in the most convenientlocation for refusing and that they do not require any space on a polearm or cross bar. Also they employ very little material and are easy toproduce so that they are very mexpensive.

In refusing it is apparent that unscrewing the nuts M will not loosenthe line wires as they are clamped by the nuts l3. Consequently a newfuse link may be substituted for the blown fuse link with the utmostease.

It is to be noted particularly that this invention provides a porcelainor other similar body portion which is preferably held in compressionand which carries a fuse structure. The particular form of fuseconstruction may, of course, be varied without departing from the spiritof this invention.

It is to be understood that these suspension fuses may be placedhorizontally, vertically or at an angle or in any desired position, andthat the fuse link may be above, to the side, or below the porcelainbody portion as desired.

Although the invention has been described in considerable detail, it isto be understood that the description is intended as illustrative ratherthan limiting, as the invention may be variously embodied and is to beinterpreted as claimed.

I claim:

1. A fuse construction comprising a body portion formed of relativelybrittle insulating material and having flat ends and having pairs ofdiametrically opposed, longitudinally extending grooves therein, saidbody portion having spaced holes extending transversely from one grooveto the diametrically opposite groove and adapted to receive loopedconductors with the loop of one conductor interlinking with the loop ofthe other conductor and spaced therefrom by the insulating body portion,whereby said insulating body portion is put under compression, metalterminal members carried by the ends of the body portion and securedagainst the end faces thereof and projecting outwardly therefrom andhaving means for receiving conductors, a fuse link extending from oneterminal member to the other terminal member longitudinally of said bodyportion, and clamping means carried by said terminal members forremovably clamping said fuse link.

2. A fuse construction comprising a body portion formed of relativelybrittle insulating material and having pairs of diametrically opposed,longitudinally extending grooves therein, said body portion havingspaced holes extending transversely from one groove to the diametricallyopposite groove and adapted to receive looped conductors with the loopof one conductor interlinking with the loop of the other conductor andspaced therefrom by the insulating body portion, whereby said insulatingbody portion is put under compression, said body portion having fiatends, metal terminal members secured to the flat ends of said bodyportion and projecting laterally therefrom, said terminal members beinglocated within the loops of said conductors, clamping means carried bysaid terminal members for receiving the ends of conductors, a fuse linkextending from one terminal member to the other terminal member and heldin spaced relation to said body portion, and means for clamping the endsof the fuse link to the terminal members.

3. A fuse construction comprising a body portion formed of relativelybrittle insulating material and having pairs of diametrically opposed,longitudinally extending grooves therein, said body portion havingspaced holes extending transversely from one groove to the diametricallyopposite groove and adapted to receive looped conductors with the loopof one conductor interlinking with the loop of the other conductor andspaced therefrom by the insulating body portion, whereby said insulatingbody portion is put under compression, said body portion having fiatends, terminal members secured to the flat ends of said body portion andprojecting outwardly therefrom and having means for receivingconductors, and fuse means normally electrically connecting saidterminal members and located oppositely and paralleling a portion ofsaid body between adjacent grooves.

RAMESIS ALFONSO HAMMACK.

